Phenol-soluble modulin

Phenol-soluble modulins (PSM) are a family of proteintoxins that are soluble in phenols, that are produced by CA-MRSA, and which are thought to be a possible cause of severe infections.[1]

Non-methicillin resistant bacteria were not found to produce these toxins. Although PSM toxins are produced in all methicillin-resistant Staphylococcus aureus strains, the more virulent CA-MRSA strains are typically associated with higher production. Genetic analysis demonstrated that the PSM-alpha protein, product of the psm-alpha gene cluster, was associated with enhanced virulence and enhanced destruction of white blood cells, presumably the key to the higher infectivity. However, expression of the psm-alpha genes appeared to vary, dependent upon unknown factors specific to each particular infection.[2]